Delayed union and nonunion are uncommon complications of femoral supracondylar osteotomy, and repair attempts usually involve reopening the medial side and readjusting the compression plate. However, the author suggests that better results can be obtained in these cases if the medial hardware is left intact and a T-plate is applied to the lateral side with compression and bone grafting. In lateral compartment arthritis of the knee, a femoral supracondylar osteotomy will return the mechanical axis of the knee to normal if the medial side is in good condition, and will usually produce long-term pain relief. The results are generally good, because 60% to 80% of the load on the knee is normally concentrated on the medial side.